This study investigates the use of the alkylating agent Temozolomide in patients with anaplastic astrocytoma at first relapse. Patients are randomized receiving either Temozolomide or Procarbazine. Those patients who are randomized to receive Temozolomide undergo pharmacokinetic blood draws during the time of the first dosing, requiring GCRC facilities. Currently, five patients have been enrolled in this study and results are not yet available in terms of response rates.